World Vegetable Center — Mungbean, a path out of poverty?

Mungbean Seeds

As a 2018 World Food Prize Borlaug-Ruan Intern, I have the amazing opportunity to conduct innovative research at the World Vegetable Center — South Asia Office located in Hyderabad, India. The World Vegetable Center organization is one of the world’s most renowned agricultural research organizations dedicated to promoting vegetables for development to relieve vitamin and mineral deficiencies. World Vegetable Center is headquartered in Tainan, Taiwan with regional offices located around the world. The Asian Vegetable Research and Development Center (AVRDC), was established on May 22, 1971, its core mission is “research and development to realize the potential of vegetables for healthier lives and more resilient livelihoods” particularly in tropical Asia. In 2008, the organization changed its name to the World Vegetable Center to better reflect the globalization of the organization’s work in areas such as sub-Saharan Africa, Central Asia, and South Asia. World Vegetable Center has amassed the world’s largest public collection of vegetable germplasm, encompassing “more than 61,235 accessions of 440 species from 151 countries”. The seed bank holds accessions of “globally important vegetable such as tomato, onion, peppers and cabbage as well as more than 10,000 accessions of traditional vegetables”. These accessions represent the large amount of genetic diversity located in domesticated plant species which has been created through artificial selection. The collection serves as a repository of genetic traits that plant breeders can use to combat new challenges from agricultural pests and climate change by breeding more resilient and resistant crop plants.

Left: Harvesting Mungbeans, Right: Mungbean Field Rows

At the World Vegetable Center — South Asia Office, the legume breeding team is working on developing mungbean (Vigna radiata) cultivars that are resistant to important pests such as Cercospora Leaf Spot (Cercospora canescens), Anthracnose (Colletotrichum truncatum), Mungbean Mosaic Virus and Bruchids (Callsobruchus ssp.). Mungbean is an important pulse crop grown in areas throughout Asia and are commonly used for bean sprouts. Mungbean matures in about two months which allows it to be grown in between cereal crops such as wheat and rice. Farmers can produce another viable food crop during a period the field typically lies fallow. Mungbeans can utilize nitrogen fixation through a symbiotic relationship with specific bacteria that live in root nodules, this ability reduces the need for nitrogen fertilizer inputs and increases soil fertility. Mungbean has promise for increased production through small-holder farmers that often lack the resources to purchase inputs and to increase farmer’s annual income.

Bruchid Beetles and Seed Damage

My research experiment involves finding the mechanisms of resistance in Mungbean seeds that prevent or deter egg laying and feeding from Bruchid beetles and larvae. Physical seed traits that are being studied include seed color, seed size, seed hardness, seed coat hardness seed coat percentage, seed volume and weight. The goal of the experiment is to establish what traits or combination thereof results in a resistant mungbean. Consumers prefer a mungbean with a shiny green seed coat, but these varieties are highly susceptible to Bruchids. To improve seed quality in these varieties will require a deeper understanding of what traits influence Bruchid resistance. Bruchids are a major storage pest in mungbeans, storage pests are organisms which damage a crop after it has been harvested. Bruchid beetles contaminate the seed in the field or once the seed has been stored. The female bruchid beetle lays one to three eggs per seed, and typically can produce one hundred eggs. Once hatched the larva burrows into the seed and begins consuming the starch located in the seed endosperm. After pupation the beetle emerges creating a large hole in the seed with only the seed coat left, reducing seed weight and quality. Farmers can suffer heavy losses under storage conditions within a couple months. Current control methods of Bruchids under storage conditions include the use of costly toxic chemicals and or oils that can impact seed quality and food safety because they must be directly applied to the seed. Severe sickness has been reported when chemical residue on the seed was consumed. Through this research we hope to provide plant breeders with data of what traits impact Bruchid resistance. Plant breeders then can develop mungbean cultivars with innate resistance to Bruchids reducing the need for the use of toxic and expensive chemicals, and maintain good seed quality.

Visiting Mungbean Field

Comment Section Discussion Points:

  • Should researchers continue to look for innate resistance or look toward other advanced breeding methods such as genetic engineering to accomplish resistance?
  • Why is it important that institutions safeguard agricultural genetic resources even though certain crops or cultivars are currently underutilized or poor yielding?
  • Should mungbeans become more popular to consume or grow in developed countries?
  • What other methods of control could be used to prevent Bruchid damage?
  • Are there any potential drawbacks of farmers adopting mungbeans?

Glossary:

Accession: An individual plant variety or cultivar usually stored in the form of seeds or propagative material.

Germplasm: Living genetic resources such as seeds or tissues that are maintained for plant or animal breeding.

Fallow: (of farmland) ploughed and harrowed but left for a period without being sown in order to restore its fertility or to avoid surplus production.

Pulse: The edible seed of a leguminous plant, for example a chickpea, lentil, or bean.

Legume: A leguminous plant (member of the pea family), especially one grown as a crop.

References:

“The Center at a Glance.” World Vegetable Center, avrdc.org/about-avrdc/about-us/.

Beck, Christopher W., and Lawrence S. Blumer. “Life Cycle of Bean Beetles, Callosobruchus Maculatus (Coleoptera: Chrysomelidae).” Carolina Biological Supply: World-Class Support for Science & Math, www.carolina.com/teacher-resources/Interactive/life-cycle-of-bean-beetles/tr25103.tr.

Cruz, L.P., de Sá, L.F.R., Santos, L.A. et al. J Pest Sci (2016) 89: 117. https://doi.org/10.1007/s10340-015-0657-z

Maharjan, R., Yi, H., Kim, H. et al. Appl Entomol Zool (2018) 53: 55. https://doi.org/10.1007/s13355-017-0524-x

Seram, Devina, et al. “Resistance Determination of a South Indian Bruchid Strain against Rice Bean Landraces of Manipur (India).” Journal of Stored Products Research, vol. 69, 22 Aug. 2016, pp. 199–206., doi:10.1016/j.jspr.2016.08.008.

Soumia, P.S., Srivastava, C., Dikshit, H.K. et al. Proc. Natl. Acad. Sci., India, Sect. B Biol. Sci. (2017) 87: 551. https://doi.org/10.1007/s40011-015-0635-5

War AR, Murugesan S, Boddepalli VN, Srinivasan R and Nair RM (2017) Mechanism of Resistance in Mungbean [Vigna radiata (L.) R. Wilczek var. radiata] to Bruchids, Callosobruchus spp. (Coleoptera: Bruchidae). Front. Plant Sci. 8:1031. doi: 10.3389/fpls.2017.01031

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